# demo05_if.py
# if 0, "", [], (), {}, None  -> False
# 特殊写法
if None:  # None -> False
    print("None yes")
else:
    print("None no")

if []:  # [] () {}: 空容器 -> False
    print("[] YES")
else:
    print("[] No")
if " ":
    print("YES~")
if "":  # 空字符串(长度为0的字符串, len)  ->  False
    print("空字符串 Yes")
else:
    print("空字符串 No")

if 0:  # 0 -0  0.0   -0.0  ->  False
    print("0 Yes")
else:
    print("0 No")

if 3 > 4:  # 3 > 0: True -> Yes   3 > 4: False -> No
    print("Yes")
else:
    print("No")


